Simulating a meat-free America

Consumers have the choice of eating animal- or plant-based food products. Credit: PNAS

(Phys.org)—A pair of researchers affiliated with both Virginia Polytechnic Institute and the U.S. Department of Agriculture has conducted an intriguing exercise—simulating the impact on the American diet and changes in greenhouse gas emissions if animal food products were completely eliminated from production, consumption and sale in the US. In their paper published in Proceedings of the National Academy of Sciences, Robin White and Mary Beth Hall describe how they built their simulation and what was revealed by running it.

Over the past couple of decades, many inside and out of the science community have suggested that the United States and other countries would be better off if we all stopped eating animal products, e.g. meat, dairy, poultry, etc. Water and land used to grow animal feed, for example, could instead be used to grow human crop foods. Also, getting rid of all those animals would surely reduce the amount of greenhouse gases emitted, both from methane emitted directly from the animals and from exhaust emitted by tractors growing plants to feed the animals. But until now, no one has put this theory to the test. In this new effort, the researchers created their simulation by envisioning the U.S. as it is now, but without any animals grown to produce food products and no animal food products being imported into the country.

After entering statistics related to crops grown for feed, water used grow it, estimates of methane emitted and multiple other factors, the researchers ran the simulation and analyzed resulting data. Removing animals from the food business, they report, resulted in 23 percent more food grown for human consumption due to conversion of land currently used for feed production to crops for human consumption. But still, even with all that new food, the researchers also found that if all Americans switched to a vegan diet, there would be mass deficiencies in minerals, vitamins and fatty acids among the populace.

They also note that approximately 16 million people are employed in the animal food business, which they did not add to their simulation, but which would have to be accounted for in real-world estimations. They also found that there would be a reduction in greenhouse gas emissions (approximately 28 percent), but not as much as expected due to the need to synthesize fertilizers to replace those created by farm animals. They suggest their simulation shows that adopting a strategy to benefit society, even one that seems simple at the outset, may not be as clear-cut as it might seem.

More information:
Robin R. White et al. Nutritional and greenhouse gas impacts of removing animals from US agriculture, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1707322114

AbstractAs a major contributor to agricultural greenhouse gas (GHG) emissions, it has been suggested that reducing animal agriculture or consumption of animal-derived foods may reduce GHGs and enhance food security. Because the total removal of animals provides the extreme boundary to potential mitigation options and requires the fewest assumptions to model, the yearly nutritional and GHG impacts of eliminating animals from US agriculture were quantified. Animal-derived foods currently provide energy (24% of total), protein (48%), essential fatty acids (23–100%), and essential amino acids (34–67%) available for human consumption in the United States. The US livestock industry employs 1.6 × 106 people and accounts for $31.8 billion in exports. Livestock recycle more than 43.2 × 109 kg of human-inedible food and fiber processing byproducts, converting them into human-edible food, pet food, industrial products, and 4 × 109 kg of N fertilizer. Although modeled plants-only agriculture produced 23% more food, it met fewer of the US population's requirements for essential nutrients. When nutritional adequacy was evaluated by using least-cost diets produced from foods available, more nutrient deficiencies, a greater excess of energy, and a need to consume a greater amount of food solids were encountered in plants-only diets. In the simulated system with no animals, estimated agricultural GHG decreased (28%), but did not fully counterbalance the animal contribution of GHG (49% in this model). This assessment suggests that removing animals from US agriculture would reduce agricultural GHG emissions, but would also create a food supply incapable of supporting the US population's nutritional requirements.

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It gave us an edge when food availability was very seasonal. That is no longer the case.

A healthy vegan diet isn't easy to do and requires a lot of work and discipline.

I think in the age of supermarkets it's quite easy to do. It may not be tasty to do, but I think it would be doable without more work than we have now (assuming you prepare your own food and don't use preprocessed products much...which people shouldn't in any case. I find preparing food fresh is a lot more tasty and also - overall - considerably cheaper.)

I"m surprised that the greenhouse gas emissions drop wasn't larger (I assume they mean the drop in the agricultural component of the emissions, it can't possibly be that large a drop in total emissions.)

"...the researchers also found that if all Americans switched to a vegan diet, there would be mass deficiencies in minerals, vitamins and fatty acids among the populace."

I find the hypothesis curious considering animal agriculture involves mostly herbivorous animals who, by definition, consume exclusively plants to get 100% of their nutritional needs met and humans then eat the bodies of the herbivores to get the same nutrition they obtained from plants. By not eating animals and eating only plants, it stands to reason that we will also get all our nutrients from plants and no one has to die in the process. There's no magic process by which other mammals convert plants to nutrition. We do this too.

Considering 2-3% of the current population is vegan and the drug stores are packed with bottles of vitamins, minerals and supplements, those ain't being stocked in such quantities to help us vegans make up for *our* deficiencies, but rather for the 97-98% who eat animal-based diets.

Pretty much agreed, I mean some people have certain dispositions in which more protein is needed though.Anyway my point is that we are near a point where we don't have to kill animals to have meat products, "clean" or no-kill (ethical) meat. Additionally, it probably won't be too long to have a 100% biosynthesis of vitamins or proteins commonly found in animal products even if the angle is "Certain amino acids are strictly found in other herbivores". Take for instance the advent of the lab grown meat, and bioprinters as the mechanism for this. Or even http://pubs.acs.o....6b00395 and related studies. So we can all go trad-vegan(vegetation only, or no-kill transvegan)

Well, the vitamins is a bit of an issue since some of these only fat soluble (A,D,E and K), so it's hard to get these from a vegan diet.Remember: Just because certain things (vitamins, minerals, etc.) are in a plant does not mean we (humans) can get at them. Plant cell structures are tough. It is no coincidence that herbivores 'chew the cud' and have much longer intestines. (e.g. eating raw carrots is not going to supply you with a lot of vitamin A - even though there's plenty in there. You just can't get at it.)

Humans try simulate this by softening up plant matter beforehand (by cooking). Problem here is that this destroys many vitamins.

Chris_Reeve

(e.g. eating raw carrots is not going to supply you with a lot of vitamin A - even though there's plenty in there. You just can't get at it.)

Just to harp on this a bit more - my physiology/anatomy prof put it in a nutshell:

"Nutrition/calories is not just about how much you put in. It's about how much you put in MINUS what comes out"

(read: what your intestines don't absorb isn't of any use to you)

Additionally, it probably won't be too long to have a 100% biosynthesis of vitamins or proteins commonly found in animal products

While I do love the idea of artificially grown meat and cell cultures as reported here:https://techxplor...lls.html...the sheer amount of proteins and chemical compounds required -in a way we can absorb and have it taste and feel palatable- is staggering. My feeling is that it's going to be a couple decades, yet, before we get this in an acceptable product.

those ain't being stocked in such quantities to help us vegans make up for *our* deficiencies, but rather for the 97-98% who eat animal-based diets

erm... no

they're stocked because the typical diet contains so much sh*t due to fast foods, processing, deficiencies and the fact that too often people eat what they like rather than what is good for them (veggies are unpalatable to a lot of folk)

and people eat what they like vrs what is good usually out of ignorance or their own choice to enjoy life rather than sit a sideline watching others enjoy it (lots of people just plain enjoy food)

i am actually excited about growing artificial meat for multiple reasons, be it eating or transplant material for medicine

For sure. The whole area of artificially grown food cultures is on my watchlist (not least of which because I think it will be an essential technology for going into space in any serious way. Getting there requires spaceships. Staying there requires growing food.)

the downfall of most vegans, really

Probably those who don't really get into the whole physiology side of it. I do think a balanced and healthy vegan diet is possible (and those videos of the vegan bodybuilder guy are downright impressive). It just requires a lot of understanding of how the body works and what it can and - most of all - cannot do. The naive approach of "I'll just cut out any animal product" just doesn't work...and it might even be dangerous when applied to their children where any inadvertent deficiency can have dire consequences.

. A healthy vegan diet isn't easy to do... A healthy vegan diet is an oxymoron.. it doesn't exist! Eat your veges scream the vegans and the corrupt, self-appointed dieticians, they fully funded by big food and big biotech.. yet.. spinach is high in oxalic acid that inflames kidneys; that can lead to kidney failure, kidney stones and blocks mineral absorption, mainly calcium..

Even a quick heating destroys 90% of B vitamins; short boiling destroys 50% of phyto-nutrients, long boiling destroys 100%; minerals are thrown out with water after boiling; nutrients in raw veges are too tightly bound up in the plant cells, (OK for cattle with 2 stomachs): juicing gets the nutrients out but when juicer blades get hot, toxic nickel and chromium is released..

possible, but only if the vegan actually does homework and learns about diet, etc...

(and those videos of the vegan bodybuilder guy are downright impressive)

not really: for starters, body building isn't just about mass as it is about definition, which is more about lack of fat than bulked musclesupplements will always be a part of this diet if you want to compete.. but you absolutely must be a master of the diet for competition: see https://www.bodyb...ek42.htm

The naive approach of "I'll just cut out any animal product" just doesn't work...and it might even be dangerous when applied to their children

agreed... IMHO it's definitely dangerous, especially as it requires a LOT more education, planning and special care

No need to wonder. Birds fly, fish breathe underwater... it's a long list. I didn't just get here, yanno.

What's puzzling is how I've managed to live for the past 13 years without consuming animal flesh or secretions and am in optimal health with no medically-detectable deficiencies. [Warning - here comes that pesky logic again] Either I and millions of other vegans are anomalies or eating a plants-only diet is perfectly healthy, as evidenced by the position of the Academy of Nutrition and Dietetics who state exactly that. Google that instead of "seabirds".

its pretty obvious from your post that theres a whole lot you dont understand and cant be bothered to find out.

I've been studying this a long time. How'd you come to your "pretty obvious" but erroneous conclusion?

humans then eat the bodies of the herbivores to get the same nutrition they obtained from plants

- So according to you, eating plants is the same thing as eating meat. Which is nonsense.

"Vegetarians and vegans may need to supplement with some of them in order to maintain optimal health.Vitamin B12. Vitamin B12 is an essential nutrient found in virtually no plant foods. ...Creatine. ...Carnosine. ...Cholecalciferol (Vitamin D3) ...Docosahexaenoic Acid (DHA) ...Heme-iron. ...Taurine..."

-Plus I suspect that our microbiome requires biota that we get from eating meat for a million years, and nowhere else.

"Long term vegetarianism can lead to genetic mutations which raise the risk of heart disease and cancer, scientists have found. Populations who have had a primarily vegetarian diet for generations were found to be far more likely to carry DNA which makes them susceptible to inflammation."

Also

"Long term vegetarianism can lead to genetic mutations which raise the risk of heart disease and cancer, scientists have found... But it has the knock-on effect of boosting the production of arachidonic acid, which is linked to inflammatory disease and cancer. When coupled with a diet high in vegetable oils - such as sunflower oil - the mutated gene quickly turns fatty acids into dangerous arachidonic acid.

"The finding may help explain previous research which found vegetarian populations are nearly 40 per cent more likely to suffer colorectal cancer than meat eaters, a finding that has puzzled doctors because eating red meat is known to raise the risk."

-But of course they use the article to imply that this is a bad thing.

""I mean, I love meat," says microbiologist Lawrence David, who contributed to the study and is now at Duke University.

"But I will say that I definitely feel a lot more guilty ordering a hamburger ..."

Yeah here you go

"Where do all those trillions of bacteria come from? It turns out that, for the most part, we're voluntarily putting them in our mouths around three times a day. "You get an ongoing input of microbes from your environment—microbes you eat on food itself," says Knight, who directs of the Center for Microbiome Innovation at the University of California at San Diego.Read more: http://www.smiths...6877l.99

"Because microbes are everywhere—on the table, in the air, on the surface of the muffin you left out on the counter—you're also adding new microbes to the mix. Some stroll through your body like polite tourists. Others stick around and interact with the locals. Every bite has the potential to alter the microbiome, and subsequently human health. But researchers have yet to figure out how."

-Nice article. We change our biome not only by feeding and starving what is already there, but by ingesting new along with the food we eat.

And as we've been eating meat throughout our entire development, we have probably developed a symbiotic relationship not just with the nutrients we get from it but also the meat biota which continues to live on in our gut.